The present invention concerns an extension guide for drawers comprising a carcass rail to be fixed to a furniture carcass, a drawer rail to be fixed to the drawer, and a central rail mounted movably between the carcass rail and the drawer rail. The relative movement sequence of the rails is determined by a positive control, and the positive control has a synchronization wheel which is in the form of a gear and which cooperates with a running surface arranged or formed on the rails and/or with a running surface of a carriage mounted displaceably between the rails.
The invention further concerns an article of furniture having a drawer extension guide of the kind to be described.
Positive controls of a drawer extension guide serve to exactly establish the relative movement sequence of the rails and/or the relative movement sequence of carriages mounted between the rails. In this connection, numerous configurations of such positive controls are known (for example DE 10 2005 016 418 A1), wherein either the movement sequence of the rails relative to each other, the movement sequence of the rails relative to the carriages, or the movement sequence of carriages which are displaceably mounted on the one hand between the carcass rail and the central rail and on the other hand between the central rail and the drawer rail is controlled. Examples of positive controls are rack-and-pinion arrangements controlling the relative movements of the rails and/or the carriages. When using such positive control systems, however, there is the danger that blocking or non-synchronous movement of a moveable rail can lead to destruction of the positive control—in particular breakage of the rack-and-pinion arrangement. Transport of the drawer extension guide as well as abusive handling (intentional improper operation of or dropping the drawer extension guide) can lead to such damage so that the drawer extension guide is no longer properly operable.